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initial forking of open-al to create multiple listeners
author Robert McIntyre <rlm@mit.edu>
date Tue, 25 Oct 2011 13:02:31 -0700
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-1:000000000000 0:f9476ff7637e
1 /**
2 * OpenAL cross platform audio library
3 * Copyright (C) 2011 by Chris Robinson
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 * Or go to http://www.gnu.org/copyleft/lgpl.html
19 */
20
21 #include "config.h"
22
23 #include "AL/al.h"
24 #include "AL/alc.h"
25 #include "alMain.h"
26 #include "alSource.h"
27
28 /* External HRTF file format (LE byte order):
29 *
30 * ALchar magic[8] = "MinPHR00";
31 * ALuint sampleRate;
32 *
33 * ALushort hrirCount; // Required value: 828
34 * ALushort hrirSize; // Required value: 32
35 * ALubyte evCount; // Required value: 19
36 *
37 * ALushort evOffset[evCount]; // Required values:
38 * { 0, 1, 13, 37, 73, 118, 174, 234, 306, 378, 450, 522, 594, 654, 710, 755, 791, 815, 827 }
39 *
40 * ALushort coefficients[hrirCount][hrirSize];
41 * ALubyte delays[hrirCount]; // Element values must not exceed 127
42 */
43
44 static const ALchar magicMarker[8] = "MinPHR00";
45
46 #define HRIR_COUNT 828
47 #define ELEV_COUNT 19
48
49 static const ALushort evOffset[ELEV_COUNT] = { 0, 1, 13, 37, 73, 118, 174, 234, 306, 378, 450, 522, 594, 654, 710, 755, 791, 815, 827 };
50 static const ALubyte azCount[ELEV_COUNT] = { 1, 12, 24, 36, 45, 56, 60, 72, 72, 72, 72, 72, 60, 56, 45, 36, 24, 12, 1 };
51
52 static struct Hrtf {
53 ALuint sampleRate;
54 ALshort coeffs[HRIR_COUNT][HRIR_LENGTH];
55 ALubyte delays[HRIR_COUNT];
56 } Hrtf = {
57 44100,
58 #include "hrtf_tables.inc"
59 };
60
61 // Calculate the elevation indices given the polar elevation in radians.
62 // This will return two indices between 0 and (ELEV_COUNT-1) and an
63 // interpolation factor between 0.0 and 1.0.
64 static void CalcEvIndices(ALfloat ev, ALuint *evidx, ALfloat *evmu)
65 {
66 ev = (M_PI/2.0f + ev) * (ELEV_COUNT-1) / M_PI;
67 evidx[0] = (ALuint)ev;
68 evidx[1] = minu(evidx[0] + 1, ELEV_COUNT-1);
69 *evmu = ev - evidx[0];
70 }
71
72 // Calculate the azimuth indices given the polar azimuth in radians. This
73 // will return two indices between 0 and (azCount [ei] - 1) and an
74 // interpolation factor between 0.0 and 1.0.
75 static void CalcAzIndices(ALuint evidx, ALfloat az, ALuint *azidx, ALfloat *azmu)
76 {
77 az = (M_PI*2.0f + az) * azCount[evidx] / (M_PI*2.0f);
78 azidx[0] = (ALuint)az % azCount[evidx];
79 azidx[1] = (azidx[0] + 1) % azCount[evidx];
80 *azmu = az - floor(az);
81 }
82
83 // Calculates the normalized HRTF transition factor (delta) from the changes
84 // in gain and listener to source angle between updates. The result is a
85 // normalized delta factor than can be used to calculate moving HRIR stepping
86 // values.
87 ALfloat CalcHrtfDelta(ALfloat oldGain, ALfloat newGain, const ALfloat olddir[3], const ALfloat newdir[3])
88 {
89 ALfloat gainChange, angleChange;
90
91 // Calculate the normalized dB gain change.
92 newGain = maxf(newGain, 0.0001f);
93 oldGain = maxf(oldGain, 0.0001f);
94 gainChange = aluFabs(log10(newGain / oldGain) / log10(0.0001f));
95
96 // Calculate the normalized listener to source angle change when there is
97 // enough gain to notice it.
98 angleChange = 0.0f;
99 if(gainChange > 0.0001f || newGain > 0.0001f)
100 {
101 // No angle change when the directions are equal or degenerate (when
102 // both have zero length).
103 if(newdir[0]-olddir[0] || newdir[1]-olddir[1] || newdir[2]-olddir[2])
104 angleChange = aluAcos(olddir[0]*newdir[0] +
105 olddir[1]*newdir[1] +
106 olddir[2]*newdir[2]) / M_PI;
107
108 }
109
110 // Use the largest of the two changes for the delta factor, and apply a
111 // significance shaping function to it.
112 return clampf(angleChange*2.0f, gainChange*2.0f, 1.0f);
113 }
114
115 // Calculates static HRIR coefficients and delays for the given polar
116 // elevation and azimuth in radians. Linear interpolation is used to
117 // increase the apparent resolution of the HRIR dataset. The coefficients
118 // are also normalized and attenuated by the specified gain.
119 void GetLerpedHrtfCoeffs(ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat (*coeffs)[2], ALuint *delays)
120 {
121 ALuint evidx[2], azidx[2];
122 ALfloat mu[3];
123 ALuint lidx[4], ridx[4];
124 ALuint i;
125
126 // Claculate elevation indices and interpolation factor.
127 CalcEvIndices(elevation, evidx, &mu[2]);
128
129 // Calculate azimuth indices and interpolation factor for the first
130 // elevation.
131 CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
132
133 // Calculate the first set of linear HRIR indices for left and right
134 // channels.
135 lidx[0] = evOffset[evidx[0]] + azidx[0];
136 lidx[1] = evOffset[evidx[0]] + azidx[1];
137 ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
138 ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
139
140 // Calculate azimuth indices and interpolation factor for the second
141 // elevation.
142 CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
143
144 // Calculate the second set of linear HRIR indices for left and right
145 // channels.
146 lidx[2] = evOffset[evidx[1]] + azidx[0];
147 lidx[3] = evOffset[evidx[1]] + azidx[1];
148 ridx[2] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[0]) % azCount[evidx[1]]);
149 ridx[3] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[1]) % azCount[evidx[1]]);
150
151 // Calculate the normalized and attenuated HRIR coefficients using linear
152 // interpolation when there is enough gain to warrant it. Zero the
153 // coefficients if gain is too low.
154 if(gain > 0.0001f)
155 {
156 ALdouble scale = gain * (1.0/32767.0);
157 for(i = 0;i < HRIR_LENGTH;i++)
158 {
159 coeffs[i][0] = lerp(lerp(Hrtf.coeffs[lidx[0]][i], Hrtf.coeffs[lidx[1]][i], mu[0]),
160 lerp(Hrtf.coeffs[lidx[2]][i], Hrtf.coeffs[lidx[3]][i], mu[1]),
161 mu[2]) * scale;
162 coeffs[i][1] = lerp(lerp(Hrtf.coeffs[ridx[0]][i], Hrtf.coeffs[ridx[1]][i], mu[0]),
163 lerp(Hrtf.coeffs[ridx[2]][i], Hrtf.coeffs[ridx[3]][i], mu[1]),
164 mu[2]) * scale;
165 }
166 }
167 else
168 {
169 for(i = 0;i < HRIR_LENGTH;i++)
170 {
171 coeffs[i][0] = 0.0f;
172 coeffs[i][1] = 0.0f;
173 }
174 }
175
176 // Calculate the HRIR delays using linear interpolation.
177 delays[0] = (ALuint)(lerp(lerp(Hrtf.delays[lidx[0]], Hrtf.delays[lidx[1]], mu[0]),
178 lerp(Hrtf.delays[lidx[2]], Hrtf.delays[lidx[3]], mu[1]),
179 mu[2]) * 65536.0f);
180 delays[1] = (ALuint)(lerp(lerp(Hrtf.delays[ridx[0]], Hrtf.delays[ridx[1]], mu[0]),
181 lerp(Hrtf.delays[ridx[2]], Hrtf.delays[ridx[3]], mu[1]),
182 mu[2]) * 65536.0f);
183 }
184
185 // Calculates the moving HRIR target coefficients, target delays, and
186 // stepping values for the given polar elevation and azimuth in radians.
187 // Linear interpolation is used to increase the apparent resolution of the
188 // HRIR dataset. The coefficients are also normalized and attenuated by the
189 // specified gain. Stepping resolution and count is determined using the
190 // given delta factor between 0.0 and 1.0.
191 ALuint GetMovingHrtfCoeffs(ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat delta, ALint counter, ALfloat (*coeffs)[2], ALuint *delays, ALfloat (*coeffStep)[2], ALint *delayStep)
192 {
193 ALuint evidx[2], azidx[2];
194 ALuint lidx[4], ridx[4];
195 ALfloat left, right;
196 ALfloat mu[3];
197 ALfloat step;
198 ALuint i;
199
200 // Claculate elevation indices and interpolation factor.
201 CalcEvIndices(elevation, evidx, &mu[2]);
202
203 // Calculate azimuth indices and interpolation factor for the first
204 // elevation.
205 CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
206
207 // Calculate the first set of linear HRIR indices for left and right
208 // channels.
209 lidx[0] = evOffset[evidx[0]] + azidx[0];
210 lidx[1] = evOffset[evidx[0]] + azidx[1];
211 ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
212 ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
213
214 // Calculate azimuth indices and interpolation factor for the second
215 // elevation.
216 CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
217
218 // Calculate the second set of linear HRIR indices for left and right
219 // channels.
220 lidx[2] = evOffset[evidx[1]] + azidx[0];
221 lidx[3] = evOffset[evidx[1]] + azidx[1];
222 ridx[2] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[0]) % azCount[evidx[1]]);
223 ridx[3] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[1]) % azCount[evidx[1]]);
224
225 // Calculate the stepping parameters.
226 delta = maxf(floor(delta*(Hrtf.sampleRate*0.015f) + 0.5), 1.0f);
227 step = 1.0f / delta;
228
229 // Calculate the normalized and attenuated target HRIR coefficients using
230 // linear interpolation when there is enough gain to warrant it. Zero
231 // the target coefficients if gain is too low. Then calculate the
232 // coefficient stepping values using the target and previous running
233 // coefficients.
234 if(gain > 0.0001f)
235 {
236 ALdouble scale = gain * (1.0/32767.0);
237 for(i = 0;i < HRIR_LENGTH;i++)
238 {
239 left = coeffs[i][0] - (coeffStep[i][0] * counter);
240 right = coeffs[i][1] - (coeffStep[i][1] * counter);
241
242 coeffs[i][0] = lerp(lerp(Hrtf.coeffs[lidx[0]][i], Hrtf.coeffs[lidx[1]][i], mu[0]),
243 lerp(Hrtf.coeffs[lidx[2]][i], Hrtf.coeffs[lidx[3]][i], mu[1]),
244 mu[2]) * scale;
245 coeffs[i][1] = lerp(lerp(Hrtf.coeffs[ridx[0]][i], Hrtf.coeffs[ridx[1]][i], mu[0]),
246 lerp(Hrtf.coeffs[ridx[2]][i], Hrtf.coeffs[ridx[3]][i], mu[1]),
247 mu[2]) * scale;
248
249 coeffStep[i][0] = step * (coeffs[i][0] - left);
250 coeffStep[i][1] = step * (coeffs[i][1] - right);
251 }
252 }
253 else
254 {
255 for(i = 0;i < HRIR_LENGTH;i++)
256 {
257 left = coeffs[i][0] - (coeffStep[i][0] * counter);
258 right = coeffs[i][1] - (coeffStep[i][1] * counter);
259
260 coeffs[i][0] = 0.0f;
261 coeffs[i][1] = 0.0f;
262
263 coeffStep[i][0] = step * -left;
264 coeffStep[i][1] = step * -right;
265 }
266 }
267
268 // Calculate the HRIR delays using linear interpolation. Then calculate
269 // the delay stepping values using the target and previous running
270 // delays.
271 left = delays[0] - (delayStep[0] * counter);
272 right = delays[1] - (delayStep[1] * counter);
273
274 delays[0] = (ALuint)(lerp(lerp(Hrtf.delays[lidx[0]], Hrtf.delays[lidx[1]], mu[0]),
275 lerp(Hrtf.delays[lidx[2]], Hrtf.delays[lidx[3]], mu[1]),
276 mu[2]) * 65536.0f);
277 delays[1] = (ALuint)(lerp(lerp(Hrtf.delays[ridx[0]], Hrtf.delays[ridx[1]], mu[0]),
278 lerp(Hrtf.delays[ridx[2]], Hrtf.delays[ridx[3]], mu[1]),
279 mu[2]) * 65536.0f);
280
281 delayStep[0] = (ALint)(step * (delays[0] - left));
282 delayStep[1] = (ALint)(step * (delays[1] - right));
283
284 // The stepping count is the number of samples necessary for the HRIR to
285 // complete its transition. The mixer will only apply stepping for this
286 // many samples.
287 return (ALuint)delta;
288 }
289
290 ALCboolean IsHrtfCompatible(ALCdevice *device)
291 {
292 if(device->FmtChans == DevFmtStereo && device->Frequency == Hrtf.sampleRate)
293 return ALC_TRUE;
294 ERR("Incompatible HRTF format: %s %uhz (%s %uhz needed)\n",
295 DevFmtChannelsString(device->FmtChans), device->Frequency,
296 DevFmtChannelsString(DevFmtStereo), Hrtf.sampleRate);
297 return ALC_FALSE;
298 }
299
300 void InitHrtf(void)
301 {
302 const char *fname;
303 FILE *f = NULL;
304
305 fname = GetConfigValue(NULL, "hrtf_tables", "");
306 if(fname[0] != '\0')
307 {
308 f = fopen(fname, "rb");
309 if(f == NULL)
310 ERR("Could not open %s\n", fname);
311 }
312 if(f != NULL)
313 {
314 const ALubyte maxDelay = SRC_HISTORY_LENGTH-1;
315 ALboolean failed = AL_FALSE;
316 struct Hrtf newdata;
317 ALchar magic[9];
318 ALsizei i, j;
319
320 if(fread(magic, 1, sizeof(magicMarker), f) != sizeof(magicMarker))
321 {
322 ERR("Failed to read magic marker\n");
323 failed = AL_TRUE;
324 }
325 else if(memcmp(magic, magicMarker, sizeof(magicMarker)) != 0)
326 {
327 magic[8] = 0;
328 ERR("Invalid magic marker: \"%s\"\n", magic);
329 failed = AL_TRUE;
330 }
331
332 if(!failed)
333 {
334 ALushort hrirCount, hrirSize;
335 ALubyte evCount;
336
337 newdata.sampleRate = fgetc(f);
338 newdata.sampleRate |= fgetc(f)<<8;
339 newdata.sampleRate |= fgetc(f)<<16;
340 newdata.sampleRate |= fgetc(f)<<24;
341
342 hrirCount = fgetc(f);
343 hrirCount |= fgetc(f)<<8;
344
345 hrirSize = fgetc(f);
346 hrirSize |= fgetc(f)<<8;
347
348 evCount = fgetc(f);
349
350 if(hrirCount != HRIR_COUNT || hrirSize != HRIR_LENGTH || evCount != ELEV_COUNT)
351 {
352 ERR("Unsupported value: hrirCount=%d (%d), hrirSize=%d (%d), evCount=%d (%d)\n",
353 hrirCount, HRIR_COUNT, hrirSize, HRIR_LENGTH, evCount, ELEV_COUNT);
354 failed = AL_TRUE;
355 }
356 }
357
358 if(!failed)
359 {
360 for(i = 0;i < HRIR_COUNT;i++)
361 {
362 ALushort offset;
363 offset = fgetc(f);
364 offset |= fgetc(f)<<8;
365 if(offset != evOffset[i])
366 {
367 ERR("Unsupported evOffset[%d] value: %d (%d)\n", i, offset, evOffset[i]);
368 failed = AL_TRUE;
369 }
370 }
371 }
372
373 if(!failed)
374 {
375 for(i = 0;i < HRIR_COUNT;i++)
376 {
377 for(j = 0;j < HRIR_LENGTH;j++)
378 {
379 ALshort coeff;
380 coeff = fgetc(f);
381 coeff |= fgetc(f)<<8;
382 newdata.coeffs[i][j] = coeff;
383 }
384 }
385 for(i = 0;i < HRIR_COUNT;i++)
386 {
387 ALubyte delay;
388 delay = fgetc(f);
389 newdata.delays[i] = delay;
390 if(delay > maxDelay)
391 {
392 ERR("Invalid delay[%d]: %d (%d)\n", i, delay, maxDelay);
393 failed = AL_TRUE;
394 }
395 }
396
397 if(feof(f))
398 {
399 ERR("Premature end of data\n");
400 failed = AL_TRUE;
401 }
402 }
403
404 fclose(f);
405 f = NULL;
406
407 if(!failed)
408 Hrtf = newdata;
409 else
410 ERR("Failed to load %s\n", fname);
411 }
412 }